Optical coherence tomography (OCT) is a type of advanced medical imaging that uses light waves to take near-photographic quality cross-section pictures of living tissue. The test, which received regulatory approval for cardiac use in the United States in 2010, is performed as part of an angiogram.

In interventional cardiology, OCT imaging is used to take detailed images of blood vessel walls. These pictures are used to help determine the extent and burden of atherosclerotic plaques (build-up of cholesterol and other material) in your arteries. These plaques can build up and cause chest pain called angina. This detailed understanding can help an interventional cardiologist determine whether a stent is needed to treat your blockage and where to best place a stent so as to treat the blockage. After a stent has been placed, OCT can also be used to see how well the stent is covering the plaque and make certain it is expanded to the correct size for your vessel.

More recently, studies have tested whether OCT can be used to help guide an angioplasty and stent placement, rather than being used before or after the procedure. OCT-guided procedures may offer better procedural and in-hospital outcomes, and maybe even better long-term survival compared to standard angiography-guided interventional procedures. Further studies are needed to determine this however as OCT does require expertise in this area, the use of more contrast (the dye which is used to take the pictures which can impact your kidney function) and extends the length of the procedure.

How Does Optical Coherence Tomography Work?

Many people are already familiar with ultrasound, which uses sound waves to create images of internal structures in the body. OCT works similarly to ultrasound but uses infrared light instead of sound waves. In the case of OCT for cardiovascular procedures, light is emitted from a catheter that is temporarily placed in a patient’s blood vessel. The light that bounces back and is collected from the catheter provides highly detailed images of the interior of the blood vessel.

How Does Optical Coherence Tomography Work?

Many people are already familiar with ultrasound, which uses soundwaves to create images of internal structures in the body. OCT works similarly to ultrasound but uses infrared light instead of sound waves. More specifically, an optical beam is directed at the tissue to be imaged and a small portion of this light that reflects from sub-surface features is collected. These signals are transmitted to a computer program that converts them to images of the blood vessel wall.

In the case of OCT for cardiovascular procedures, a catheter is inserted through a puncture site in the skin and threated over a guidewire to the area of interest within the blood vessel. Light is emitted from a catheter and the light that bounces back is collected and analyzed to form remarkably clear and detailed images.  

Is Optical Coherence Tomography Safe?

OCT has been used in the coronary space for more than 20 years now and is widely considered to provide minimal risk to patients. Complications are rare (occurring in less than 1% of patients), but include arrhythmias (abnormal heartbeats), hypotension (low blood pressure), or blockage, dissection, or spasm of the artery. The test on its own does not use x-ray technology and therefore does not present radiation risks. However, OCT is always performed in conjunction with another imaging test called a coronary angiogram. Therefore, the risks associated with having an angiogram will apply here.

Questions to Ask Your Doctor About Optical Coherence Tomography (OCT)

Please print this list of questions here. Take them with you to the doctor and share them with friends and loved ones when you are encouraging them to see their doctors.